Telephone-transmitter.



No. 764,055. PATENTED JULY 5, 1904. D. G. JACKSON.

TELEPHONE TRANSMITTER.

APPLICATION FILED SEPT. 26. 1902.

N0 MODEL.

kw. E

Inventor" ug'auj DJEEKEBTI M GWZMZW UNITED STATES Patented July 1904.

PATENT OFFICE- TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 764,055, dated July 5, 1904.

Application filed September 26, 1902. Serial No. 124,962. (No model.)

To all 1071 0772, it may concern:

Be it known that I, DUGALD O. JACKSON, a citizen of the United States, residing at Madison,in the county of Dane and State of Wisconsin, have invented a certain new and useful Improvement in Telephone-Transmitters, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to telephone-transmitters, and has for its object the provision of an improved form of batterytransmitter of the type in which comminuted carbon or equivalent material is interposed between the electrodes.

The particular object of my invention con sists in the provision of an improved and simplified chamber within which the comminuted carbon is to be placed.

My invention contemplates the provision of an improved chamber which incloses the electrodesand which permits the relative movement thereof. At the same time the chamber retains the comminuted material in its proper disposition between the electrodes.

I accomplish the. objects of myinvention by providing a preferably cylindrical wall in the shape of a short tube within which the comminuted carbon is contained. This short tube is preferably lined with insulating material to prevent the direct electrical contact of the carbon with the cylindrical wall. Rigidly secured to the said cylindrical wall and projecting into one end thereof I provide the stationary electrode of the microphone. The movable electrode is connected with the main diaphragm of the transmitter in such a way as to be subject to vibrations caused by soundwaves. I find it desirable to mount the aforementioned cylindrical tube on the frame or casing of the transmitter and to allow the vibrating electrode to have what may be termed a plunger action within the said chamber. In order to permit the movement of this electrode within thesaid chamber and at the same time to prevent the escape of the confined carbon granules, I find it desirable to provide a bushing or packing-ring for the said plunger, as wlll be hereinafter more fully set forth.

Myinvention will be best understood by reference to the accompanying drawings, in which- Figure 1 is a rear view of the transmitter, the inclosing casing being removed to show the interior construction. Fig. 2 is a vertical sectional view on line 2 2 of Fig. 1, parts of the transmitter being shown in elevation. Fig. 3 is an enlarged sectional view of the microphone and the transmitter-diaphragm. Fig. 4 is a view of the elements shown in Fig. 3 before assembly.

Like parts are indicated by similar characters of reference throughout the different figures.

The general characteristics of my improved transmitter are similar to those found in other microphone-transmitters.

I desirably provide an inclosing casing consisting of a rather heavy annular ring 1, to which is secured the back part of the casing 2 and into which is screwed the customary mouthpiece 3. To this annular ring 1 is also screwed the supporting-bracket 4:. The diaphragm 5 is provided with a folded rubber ring 6 and is held firmly against the ring 1 of the transmitter-casing by the spring-clips 7 7 each of which is'provided with a rubber solepiece 8. The bracket 4 is provided with a hole 9 and a set-screw 10, adapted to secure in proper adjustment the stem 11, which car ries the back electrode 12. This stem is provided with a threaded disk 13, adapted to screw into the cylindrical tube 1 1. The tube 1 1 is thus rigidly connected, through the bracket Lwith the casing of the transmitter. A distance-piece 15, provided with'a lining of paper or cloth 16, is also screwed into the tube 14, the distance-piece 15 and the disk 13 being brought into contact, as best illustrated in Fig. 3. A ring 17 also screws into the tube M from the other end, this ring 17 being provided on its inside edge with a ring of felt or plush or other cellular material 18.

The front electrode 19,which, like the electrode 12, may desirably be made of polished carbon, is carried by the plunger 20. This plunger is provided with a stem having a shoulder 21 and a threaded portion 22, adapted to pass through a hole in the diaphragm 5 and receive a clamping nut 23. Thus the diaphragm 5 is rigidly connected with the front electrode 19 and the plunger 20, so that the plunger and electrode are subject to soundvibrations of the diaphragm.

The chamber formed by the two electrodes and the ring 15 is filled with comminuted carbon 24, the said carbon being retained in place within the chamber partly by the ring of felt 18. This ring of felt is adapted to fit loosely about the plunger 20, so as to permit a motion of the plunger as inserted by the diaphragm 5 within the chamber containing the comminuted carbon, and at the same time it prevents the escape of the inclosed granules.

A wire 25 forms the circuit connection between the insulated transmitter-terminal 26 and the front electrode 19. The back electrode 12 is electrically connected, through the stem 11 and the bracket 1, with the other transmitter-terminal 27.

The above description will make clear the operation of my improved transmitter, it being evident that with the vibrations of the diaphragm and front electrode the distance between the electrodes 19 and 12 will be varied. The fact that the electrodes project bodily within the chamber and are partially surrounded by the carbon granules is a desirable feature in that the comminuted material is stirred up by the relative movement of electrodes, and packing is thereby prevented. The plush or felt ring 18, surrounding the plunger 20, allows the utmost freedom for the movement of the plunger with the diaphragm and at the same time effectively confines the carbon granules within their chamber.

While I have herein shown and particularly described the preferred embodiment of my invention, I do not wish to limit myself to the precise construction and arrangement herein shown; but,

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1. In a telephone-transmitter, the combination with a front wall, of adiaphragm clamped thereto, a supporting-bracket bridging said Wall at the rear thereof, a stem adjustably secured in said bracket and extending forwardly therefrom, a flange at the front end of said stem, an electrode-chamber adjustably engaging said flange and freely suspended therefrom, a rear electrode secured to said flange, a front electrode secured to said diaphragm and extending within said chamber, and a ring of cellular material disposed between the interior walls of said chamber and the periphery of said front'electrode.

2. In atelephone-transmitter, the combination with a front wall, of a diaphragm clamped thereto, a supporting-bracket bridging across the rear of said wall, a stem adjustably secured in said bracket and extending forwardly therefrom, a threaded flange at the front end of said stem, an electrode-chamber having threaded engagement at its rear end with said flange, a rear electrode secured to said flange, a front electrode secured to said diaphragm and extending within said chamber, and a ring of cellular material disposed between the interior walls of said chamber and the periphery of said front electrode.

3. In a telephone-transmitter, the combination with a front wall, of a diaphragm clamped thereto, a supporting-bracket bridging across the rear of said wall, a stem secured in said bracket and extending forwardly therefrom, a threaded flange at the front end of said stem, a tube threaded upon its interior and engaging said flange at its rear end to be freely suspended therefrom, an electrode secured to said flange, a ring having screw-threaded engagement with the forward end of said threaded tube, a front electrode secured to said diaphragm and extending within said tube, and a ring of cellular material secured to said ring and extending between said ring and the periphery of said front electrode.

1. In a telephone-transmitter, the combination with a front wall, of a diaphragm clamped thereto, a supporting-bracket bridging across the rear of said wall, a stem secured in said bracket and extending forwardly therefrom, a threaded flange at the front end of said stem, a tube threaded upon its interior and engaging said flange at its rear end to be freely suspended therefrom, an electrode secured to said flange, a ring having screw-threaded engagement with the forward end of said threaded tube, a front electrode secured to said diaphragm and extending within said tube, a ring of cellular material secured to said ring and extending between said ring and the periphery of said front electrode, and a distance-ring engaging said threaded tube and disposed between said ring and the flange.

5. In a telephone-transmitter, the combination with a front wall, of a diaphragm clamped thereto, a supporting-bracket bridging across the rear of said wall, a stem adjustably secured in said bracket and terminating at its forward end in a threaded flange, an internallythreaded tube engaging said flange at its rear end, said flange and tube formingan electrode- IIO chamber freely suspended from said stem, a 

